Impact of body mass index on development of nontuberculous mycobacterial pulmonary disease

Current challenges in pulmonary nontuberculous mycobacterial infection: a case series with literature review

BACKGROUND

The prevalence of nontuberculous mycobacteria pulmonary disease (NTM-PD), particularly caused by Mycobacterium avium complex (MAC), is rising due to improved diagnostics, increased awareness, and more susceptible populations. NTM-PD significantly affects quality of life and imposes substantial economic costs. Understanding its clinical features, risk factors, and treatment challenges is vital for enhancing patient outcomes.

PATIENTS AND METHODS

A convenience sample from the University of Connecticut Health Center and Wayne State University involving patients with NTM-PD from 2021 to 2024 was studied retrospectively. Cases were selected to demonstrate typical diagnostic and treatment challenges, followed by a multidisciplinary roundtable discussion to examine patient-centered care strategies.

RESULTS

Analysis of six cases pinpointed chronic lung conditions and immunomodulatory therapy as key risk factors. Standard treatment, involving extensive multi-drug regimens, frequently results in poor adherence due to side effects and complex management requirements. The discussions underlined the importance of a customized, interdisciplinary approach to improve treatment effectiveness and patient quality of life.

CONCLUSIONS

NTM-PD is an escalating public health issue with notable clinical and economic consequences. Managing this disease effectively demands a comprehensive, patient-centered strategy that includes precise diagnosis, flexible treatment plans, and collaborative care.

Protein-energy restriction-induced lipid metabolism disruption causes stable-to-progressive disease shift in Mycobacterium avium-infected female mice

BACKGROUND

Disease susceptibility and progression of Mycobacterium avium complex pulmonary disease (MAC-PD) is associated with multiple factors, including low body mass index (BMI). However, the specific impact of low BMI on MAC-PD progression remains poorly understood. This study aims to examine the progression of MAC-PD in the context of low BMI, utilising a disease-resistant mouse model.

METHODS

We employed a MAC infection-resistant female A/J mouse model to compare the progression of MAC-PD under two dietary conditions: one group was fed a standard protein diet, representing protein-energy unrestricted conditions, and the other was fed a low protein diet (LPD), representing protein-energy restriction.

FINDINGS

Our results reveal that protein-energy restriction significantly exacerbates MAC-PD progression by disrupting lipid metabolism. Mice fed an LPD showed elevated fatty acid levels and related gene expressions in lung tissues, similar to findings of increased fatty acids in the serum of patients who exhibited the MAC-PD progression. These mice also exhibited increased CD36 expression and lipid accumulation in macrophages upon MAC infection. In vitro experiments emphasised the crucial role of CD36-mediated palmitic acid uptake in bacterial proliferation. Importantly, in vivo studies demonstrated that administering anti-CD36 antibody to LPD-fed A/J mice reduced macrophage lipid accumulation and impeded bacterial growth, resulting in remarkable slowing disease progression.

INTERPRETATION

Our findings indicate that the metabolic status of host immune cells critically influences MAC-PD progression. This study highlights the potential of adequate nutrient intake in preventing MAC-PD progression, suggesting that targeting CD36-mediated pathways might be a host-directed therapeutic strategy to managing MAC infection.

FUNDING

This research was funded by the National Research Foundation of Korea, the Korea Research Institute of Bioscience and Biotechnology, and the Korea National Institute of Health.

Usefulness of the mini nutritional assessment short-form for evaluating nutritional status in patients with nontuberculous mycobacterial pulmonary disease: a prospective cross-sectional study

BACKGROUND

Although the Mini Nutritional Assessment (MNA) is recognized as a useful tool for evaluating nutritional status in patients with various diseases, its applicability in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) remains undetermined.

METHODS

We designed a prospective cross-sectional study to investigate whether the MNA Short-Form (MNA-SF) score can serve as a screening tool to assess the nutritional status of patients with NTM-PD. The MNA-SF was conducted upon patient enrollment, and correlation analyses were performed to compare MNA-SF scores with other nutritional measurements and disease severity. Multivariable logistic regression analyses were conducted to evaluate the association between MNA-SF scores and NTM-PD severity.

RESULTS

The 194 patients with NTM-PD included in the analysis had a median age of 65.0 (59.0-69.0) years; 59.3% (n = 115) had low MNA-SF scores (< 12). The low MNA-SF group exhibited a lower body mass index (19.7 vs. 22.4 kg/m2, p < 0.001) and fat-free mass index (14.7 vs. 15.6 kg/m2, p < 0.001) than the normal MNA-SF group, as well as higher incidences of sarcopenia (20.0% vs. 6.3%, p = 0.008) and adipopenia (35.7% vs. 5.1%, p < 0.001). However, no significant differences in calorie and protein intakes were observed between the two groups. Low MNA-SF scores were associated with radiographic severity (adjusted odds ratio 2.72, 95% confidence interval 1.38-5.36) but not with forced vital capacity.

CONCLUSIONS

The MNA-SF can effectively assess the nutritional status of patients with NTM-PD and can serve as an important clinical indicator in NTM-PD where treatment timing is determined by clinical judgment.

Time to diagnosis of nontuberculous mycobacterial pulmonary disease and longitudinal changes on CT before diagnosis

Background

The healthcare burden of nontuberculous mycobacterial pulmonary disease (NTM-PD) is increasing, but the diagnosis remains challenging and sometimes requires considerable time. This nested case-control study aims to clarify the time to diagnosis of NTM-PD, the factors that affect diagnosis and diagnostic delay, and changes in CT findings before diagnosis.

Patients and methods

We retrospectively analyzed 187 patients suspected of having NTM-PD based on computed tomography (CT) findings at our institution between January 2019 and September 2020. We investigated the time to diagnosis of NTM-PD for all suspected and diagnosed patients. Multivariate analyses identified the factors affecting diagnosis and diagnostic delay over 6 months. We also evaluated longitudinal changes in CT findings during the observation period using CT scoring system.

Results

The median times to diagnosis of NTM-PD were 71.8 months in all suspected patients and 3.2 months in only the diagnosed patients. Multivariable analysis showed that severity of the cavity domain of the CT score and anti-glycopeptidolipid (GPL)-core immunoglobulin A (IgA) antibody positivity were significantly associated with establishing the diagnosis. A low CT score in the cavity domain was a risk factor for delayed diagnosis. In patients with delayed diagnosis, the total CT score was less severe than that in the early diagnosis patients at their first visits; however, it had deteriorated prior to the diagnosis.

Conclusion

The diagnosis of NTM-PD sometimes required several years, and the absence or mild cavitation predicted a diagnostic delay. Of concern, a delay in diagnosis can result in a delay in treatment.

Non-tuberculous mycobacterial pulmonary disease (NTM-PD): Epidemiology, diagnosis and multidisciplinary management

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms that can cause significant disease in both immunocompromised and immunocompetent individuals. The incidence of NTM pulmonary disease (NTM-PD) is rising globally. Diagnostic challenges persist and treatment efficacy is variable. This article provides an overview of NTM-PD for clinicians. We discuss how common it is, who is at risk, how it is diagnosed and the multidisciplinary approach to its clinical management.

Treatment of the Less Common Nontuberculous Mycobacterial Pulmonary Disease

Nontuberculous mycobacterial pulmonary disease caused by the less common nontuberculous mycobacteria have distinct features depending on the species. Diagnostic evaluation follows the established criteria for all nontuberculous mycobacteria, but with certain qualifications given species-specific and regional differences in pathogenicity. Clinicians should first institute nonpharmacologic management and evaluate clinical, radiologic, and microbiologic factors in the decision regarding antimycobacterial therapy. Treatment is challenging, and evidence-based recommendations are limited for most species. Drug susceptibility testing is used to help with regimen selection; however, this approach is imperfect given the uncertain correlation between in vitro activity and clinical response for most drugs.

Alterations in lung and gut microbiota reduce diversity in patients with nontuberculous mycobacterial pulmonary disease

BACKGROUND/AIMS

Although the incidence of nontuberculous mycobacteria pulmonary disease (NTM-PD), a chronic infectious disease, is increasing, lung and gut microbiota dysbiosis in NTM patients has rarely been studied and was therefore the focus of this study.

METHODS

We analyzed the microbiota diversity in sputum and stool samples from 10 healthy subjects and 10 patients with NTM-PD through sequencing of the V3 and V4 regions of the 16S rRNA gene. In NTM-PD patients, we comparatively evaluated the microbiota diversity according to the body mass index (BMI), with BMI ≤ 18.5 kg/m2 defined as "underweight" and BMI > 18.5 kg/m2 as "others."

RESULTS

The sputum microbiota from NTM-PD patients tended to have lower index values of amplicon sequence variant richness, Shannon evenness, and beta diversity than those from the control group. Furthermore, NTM-PD patients with a low BMI had a lower microbiota diversity than patients with high BMI. Fecal samples from NTM-PD patients also significantly differed in alpha and beta diversity compared with the control group and exhibited a diversity pattern similar to that found in sputum samples.

CONCLUSION

Our results reveal that the lung and gut microbiota of patients with NTM-PD exhibit an altered distribution and reduced richness and diversity.

Risk Factors for Nontuberculous Mycobacterial Pulmonary Disease: A Systematic Literature Review and Meta-Analysis

BACKGROUND

Nontuberculous mycobacterial pulmonary disease (NTM-PD) is widely underdiagnosed, and certain patient groups, such as those with underlying respiratory diseases, are at increased risk of developing the disease. Understanding patients at risk is essential to allow for prompt testing and diagnosis and appropriate management to prevent disease progression.

RESEARCH QUESTION

What are the risk factors for NTM-PD that should prompt a physician to consider NTM testing and diagnosis?

STUDY DESIGN AND METHODS

Electronic searches of PubMed and EMBASE were conducted in July 2021 for the period 2011-2021. Inclusion criteria were studies of patients with NTM-PD with associated risk factors. Data were extracted and assessed using the Newcastle-Ottawa Scale. Data analysis was conducted using the R-based "meta" package. Only studies that reported association outcomes for cases with NTM-PD compared with control participants (healthy populations or participants without NTM-PD) were considered for the meta-analysis.

RESULTS

Of the 9,530 searched publications, 99 met the criteria for the study. Of these, 24 formally reported an association between possible risk factors and the presence of NTM-PD against a control population and were included in the meta-analysis. Comorbid respiratory disease was associated with a significant increase in the OR for NTM-PD (bronchiectasis [OR, 21.43; 95% CI, 5.90-77.82], history of TB [OR, 12.69; 95% CI, 2.39-67.26], interstitial lung disease [OR, 6.39; 95% CI, 2.65-15.37], COPD [OR, 6.63; 95% CI, 4.57-9.63], and asthma [OR, 4.15; 95% CI, 2.81-6.14]). Other factors noted to be associated with an increased risk of NTM-PD were the use of inhaled corticosteroids (OR 4.46; 95% CI, 2.13-9.35), solid tumors (OR, 4.66; 95% CI, 1.04-20.94) and the presence of pneumonia (OR, 5.54; 95% CI, 2.72-11.26).

INTERPRETATION

The greatest risk for NTM-PD is conferred by comorbid respiratory diseases such as bronchiectasis. These findings could help with identification of patient populations at risk for NTM-PD to drive prompt testing and appropriate initiation of therapy.

Impact of Allergic Disease on the Risk of Mycobacterial Disease

BACKGROUND

The association between allergic diseases and the risk of mycobacterial disease is unclear.

OBJECTIVE

To evaluate the association between allergic diseases and mycobacterial diseases.

METHODS

This was a population-based cohort study of 3,838,680 individuals, without prior mycobacterial disease, who participated in the 2009 National Health Screening Exam. We evaluated the incidence of mycobacterial disease (tuberculosis or nontuberculous mycobacterial infection) in participants with allergic disease (asthma, allergic rhinitis, or atopic dermatitis) and those without allergic disease. We followed the cohort up until the date of mycobacterial disease diagnosis, follow-up loss, death, or December 2018.

RESULTS

During a median follow-up of 8.3 (interquartile range, 8.1-8.6) years, 0.6% of participants developed mycobacterial disease. The incidence of mycobacterial disease was significantly higher in those with allergic diseases than in those without allergic diseases (1.0 vs 0.7/1000 person-years; P < .001), with an adjusted hazard ratio of 1.13 (95% CI, 1.10-1.17). Asthma (adjusted hazard ratio, 1.37; 95% CI, 1.29-1.45) and allergic rhinitis (adjusted hazard ratio, 1.07; 95% CI, 1.04-1.11) increased the hazard of mycobacterial disease, whereas atopic dermatitis did not. The association between allergic diseases and hazard of mycobacterial disease was more prominent in older (age ≥ 65 years, P for interaction = .012) and obese (body mass index ≥ 25 kg/m2, P for interaction < .001) participants.

CONCLUSION

Allergic diseases including asthma and allergic rhinitis were associated with an increased risk of mycobacterial disease, whereas atopic dermatitis was not.

Myosteatosis as a prognostic factor of Mycobacterium avium complex pulmonary disease

Quantitative body composition affects the prognosis of patients with Mycobacterium avium complex pulmonary disease (MAC-PD). However, whether the qualitative body composition obtained indirectly through computed tomography (CT) affects their prognosis is debatable. We retrospectively analyzed patients with MAC-PD who underwent non-contrast CT at MAC-PD diagnosis. The cross-sectional area of the erector spinae muscle (ESM area), the Hounsfield unit of the erector spinae muscle (ESM HU), and the cross-sectional area of subcutaneous fat (SQF area) were measured at the level of the first lumbar vertebra. Myosteatosis were defined below the median value of ESM HU for each sex. Of 377 patients, 45 (11.9%) died during the follow-up. Patients who died were older and had a lower ratio of females (33.3%). In body compositions, SQF area and ESM HU were lower in the patients who died. In multivariable analysis, a low ESM HU was associated with increased mortality (ESM HU adjusted hazard ratio [aHR] 0.95, 95% confidence interval [CI] 0.93-0.97) through body composition. SQF area revealed protective effects in MAC-PD patients with body mass index ≥ 18.5 kg/m2 (aHR 0.98, 95% CI 0.95-1.00). In conclusion, the decrease in ESM HU, which indirectly reflects myosteatosis, is associated with mortality in patients with MAC-PD.

Association of body size distortion with low body mass index in female patients with nontuberculous mycobacterial lung disease

BACKGROUND

We have previously reported that female patients with nontuberculous mycobacterial lung disease (NTM-LD) are thinner and eat less than healthy controls. Therefore, we hypothesized that their thinness is associated with body size misperception. The aim of this study was to clarify whether patients' body size perception (BSP) is associated with body mass index (BMI) independent of potential confounders.

METHODS

In this cross-sectional study, we assessed 81 outpatients for BSP using the Japanese version of Body Image Scale, body composition, dietary intake, and biochemical markers. As a control, we used BSP and self-reported anthropometric data from 111 healthy women collected via a web survey. First, BSP and BMI were compared between the patients and the controls. Second, patient data was compared between patients who overestimated their body size (OE, n = 31) and a control who did not (Non-OE, n = 50). Multiple regression analysis was performed to clarify the association between BSP (independent variable) and BMI (dependent variable), adjusting for potential confounders, such as age, disease duration, and nutritional factors.

RESULTS

There was a negative correlation between body size distortion and BMI in both patients and controls (p < 0.001, both). In interpatient comparisons, the OE group had significantly lower BMI and body fat percentage (p < 0.001, both), normalized energy (p = 0.037), and protein (p = 0.013) intakes, and significantly greater weight loss from age 20 (p = 0.003) than the Non-OE group. Multiple regression analysis revealed that overestimation of body size was associated with lower BMI independent of confounders, such as longer disease history, longitudinal weight loss, and nutritional factors.

CONCLUSION

These findings suggest that body size distortion is an etiological factor for lower BMI in female patients with NTM-LD. Thus, it may be important to understand the patient's body image when providing dietary advice.

Usefulness of the BACES score in nontuberculous mycobacterial pulmonary disease for various clinical outcomes

A uniform prognostic marker is needed for nontuberculous mycobacterial pulmonary disease (NTM-PD) due to the diverse clinical course. We aimed to seek the utility of the BACES score, originally derived to predict all-cause mortality, for various outcomes. To calculate the BACES score, one point was given for each of the following factors: body mass index < 18.5 kg/m², age ≥ 65 years, presence of cavities, elevated erythrocyte sedimentation rate, or male sex. The study included 681 patients, of whom 97 (14.2%), 189 (27.7%), 192 (28.2%), 143 (21.0%), 47 (6.9%), and 13 (1.9%) had BACES scores of 0 to 5. Those with greater BACES scores were more likely to experience dyspnea, body weight loss, and anorexia. With severe disease, the risk of disease progression increased while the rate of treatment culture conversion decreased. After adjustment of comorbidities, higher BACES score was independently associated with the risk of mortality from respiratory causes or infection. As a simple and efficient bedside tool for assessing the severity of NTM-PD, the BACES score has the potential to be utilized as a surrogate marker for uniform severity assessment.

Rapid diagnosis of non-tuberculous mycobacterial pulmonary diseases by metagenomic next-generation sequencing in non-referral hospitals

Objectives

The incidence of non-tuberculous mycobacterial pulmonary disease (NTM-PD) has increased steadily globally, but the current culture-based diagnosis of NTM-PD is difficult and time-consuming, leading to a high possibility of misdiagnosis. Therefore, new methods should be introduced to improve the processes for clinical diagnosis of this disease.

Methods

Our retrospective observational study enrolled 12 NTM-PD patients who were identified by way of metagenomic next-generation sequencing (mNGS), as well as the characteristic radiological presentation of slowly progressed, usually concomitant bronchiectasis, small cavitary opacity, and multiple nodules that respond poorly to empirical antibiotic therapy. These patients received the recommended drug regimen based on the identified non-tuberculous mycobacteria (NTM) species. Clinical data, including symptoms, laboratory tests, dynamic computed tomography imaging, treatment, and outcome, were recorded and analyzed.

Results

The results of mNGS were all positive, with the standard specifically mapped read numbers (SDSMRN) of NTM ranging from 1 to 766; this was confirmed in six patients via quantitative polymerase chain reaction (qPCR) analysis. The duration fromsample collection tomNGS results was 1-4 days. Among our 12 patients (except for one lost to follow-up) the CT imaging for 11 patients showed significant absorption of lesions.

Conclusions

Our results draw attention to NTM infection as a possible cause of community-acquired pneumonia, especially in patients with suggestive radiological presentation and poor responses to empirical antibiotic therapy. Our study also indicated that mNGS represented a potentially effective tool for the rapid identification of NTM in the respiratory sample. Improved clinician awareness combined with the utilization of mNGS could guide earlier diagnosis and targeted treatment, and finally improved the prognoses of patients with NTM-PD.

Healthcare use and medical cost before and after diagnosis of nontuberculous mycobacterial infection in Korea: the National Health Insurance Service-National Sample Cohort Study

BACKGROUND AND OBJECTIVE

The global prevalence and incidence of nontuberculous mycobacterial (NTM) infections are increasing; however, population-level data on healthcare use and medical costs for people with NTM infections are limited. Thus, we investigated the rates of healthcare use and medical costs of people with NTM infections in South Korea using the National Health Insurance Service-National Sample Cohort from 2002 to 2015.

METHODS

In this cohort study, people with and without NTM infection aged 20-89 years were matched 1 to 4 by sex, age, Charlson comorbidity index, and year of diagnosis. The overall and annual average healthcare use and medical costs were calculated. In addition, trends in healthcare use and medical costs for each of the 3 years before and after NTM diagnosis were investigated for people diagnosed with NTM infection.

RESULTS

A total of 798 individuals (336 men and 462 women) diagnosed with NTM infection and 3192 controls were included in the study. NTM-infected patients had significantly higher rates of healthcare use and medical costs than those in the control group (p < 0.05). NTM-infected patients showed 1.5 times the medical cost and 4.5 times the respiratory disease cost of the control group. People diagnosed with NTM infection incurred the highest medical costs in the 6 months before diagnosis.

CONCLUSION

NTM infection increases the economic burden on Korean adults. Appropriate diagnostic tests and treatment plans for NTM infections are needed to reduce the burden of the disease caused by such infection.

Nontuberculous mycobacteria infection and pulmonary disease in bronchiectasis

Background

Although interest in nontuberculous mycobacteria (NTM) infection has increased in the last decades, published data vary according to different geographical areas, diagnostic facilities and quality of study design. This study aims at assessing both prevalence and incidence of NTM infection and NTM pulmonary disease (NTM-PD) among adults with bronchiectasis, to describe patients' characteristics, therapeutic options and clinical outcomes.

Methods

Bronchiectasis adults who had been tested for NTM were enrolled at the Bronchiectasis Program of the Policlinico Hospital in Milan, Italy, from 2016 to 2018.

Results

Among the 373 patients enrolled, 26.1% had at least one respiratory sample positive for NTM and 12.6% reached a diagnosis of NTM-PD. Incidence rates for NTM infection and NTM-PD were 13 (95% CI 10-16) and 4 (95% CI 2-6) per 100 person-years, respectively. The most prevalent NTM species causing NTM-PD were M. intracellulare (38.3%), M. avium (34.0%), M. abscessus (8.5%) and M. kansasii (8.5%). Once treatment for NTM-PD was initiated, a favourable outcome was documented in 52.2% of the patients, while a negative outcome was recorded in 32.6%, including recurrence (17.4%), treatment failure (10.9%), re-infection (2.2%) and relapse (2.2%). Treatment halted was experienced in 11 (23.9%) patients.

Conclusions

NTM infection is frequent in bronchiectasis patients and the presence of NTM-PD is relevant. The low success rate of NTM-PD treatment in bronchiectasis patients requires a call to action to identify new treatment modalities and new drugs to improve patients' outcomes.

Comorbidities of nontuberculous mycobacteria infection in Korean adults: results from the National Health Insurance Service–National Sample Cohort (NHIS–NSC) database

Background

The global prevalence and incidence of nontuberculous mycobacteria (NTM) infection are increasing. However, the prevalence of NTM infection-associated comorbidities remains understudied. Thus, we investigated the comorbidities associated with NTM infection using the National Health Insurance Service-National Sample Cohort (NHIS–NSC) 2.0 database of the National Health Insurance Service (NHIS).

Methods

In this case–control study, patients with NTM infection and controls aged 20–89 years of age were matched 1:4 by sex, age, region, and income. A total of 26 comorbidities were selected based on previous reports and claims data analysis. The distribution of comorbidities was compared between patients with NTM infection and controls by sex and age using logistic regression analysis.

Results

In total, 893 patients (379 men and 514 women) with NTM infection (mean age, 56.1 years) and 3,572 controls (mean age, 55.6 years) were included. The odds ratio for prevalence of respiratory diseases, metabolic diseases, musculoskeletal disorders, gastrointestinal diseases, skin diseases, mental diseases, and neoplasms was significantly higher in patients with NTM infection than in the control group. Among comorbid diseases, the odds ratios (ORs) for the prevalence of the respiratory diseases such as bronchiectasis (OR [95% confidence interval (CI)]: 26.79 [19.69–36.45]) and interstitial pneumonitis (OR [95% CI]: 15.10 [7.15–31.89]) were the highest. No significant differences were observed in NTM infection-related comorbidities between men and women. In the younger age group (20–39 years old), the prevalence of respiratory and systemic diseases such as hypertension and diabetes was higher in the patient group than in the control group.

Conclusions

NTM infection is associated with several respiratory and systemic diseases that should be considered when providing medical care to patients with NTM infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02075-y.

Incidence of Nontuberculous Mycobacterial Pulmonary Infection, by Ethnic Group, Hawaii, USA, 2005-2019

To further clarify differences in the risk for nontuberculous mycobacterial pulmonary infection (NTM-PI) among ethnic populations in Hawaii, USA, we conducted a retrospective cohort study among beneficiaries of Kaiser Permanente Hawaii (KPH). We abstracted demographic, socioeconomic, clinical, and microbiological data from KPH electronic health records for 2005-2019. An NTM-PI case-patient was defined as a person from whom >1 NTM pulmonary isolate was obtained. We performed Cox proportional hazards regression to estimate incidence of NTM-PI while controlling for confounders. Across ethnic groups, risk for NTM-PI was higher among persons who were underweight (body mass index [BMI] <18.5 kg/m²). Among beneficiaries who self-identified as any Asian ethnicity, risk for incident NTM-PI was increased by 30%. Low BMI may increase susceptibility to NTM-PI, and risk may be higher for persons who self-identify as Asian, independent of BMI.

Management of Mycobacterium avium complex and Mycobacterium abscessus pulmonary disease: therapeutic advances and emerging treatments

Nontuberculous mycobacterial pulmonary disease (NTM-PD) remains a challenging condition to diagnose and treat effectively. Treatment of NTM-PD is prolonged, frequently associated with adverse effects and has variable success. In this review, we consider the factors influencing clinicians when treating NTM-PD and discuss outcomes from key studies on the pharmacological management of Mycobacterium avium complex pulmonary disease and M. abscessus pulmonary disease. We highlight issues relating to treatment-related toxicity and provide an overview of repurposed and emerging therapies for NTM-PD.

Female reproductive factors and incidence of non-tuberculous mycobacterial pulmonary disease among postmenopausal women in Korea

BACKGROUND

There are conflicting results regarding endogenous estrogen exposure and risk of incident non-tuberculous mycobacterial pulmonary disease (NTM-PD). In addition, the impact of hormone replacement therapy (HRT) on risk of NTM-PD is lacking. This study aimed to evaluate the impacts of endogenous estrogen exposure and HRT on risk of NTM-PD in postmenopausal women.

METHODS

This population-based cohort study consisted of 1,400,095 postmenopausal women without previous NTM-PD who participated in the 2009 national health screening exam in South Korea. The cohort was followed until the date of incident NTM-PD, death, or December 2018. We evaluated whether lifetime endogenous estrogen exposure and HRT were associated with incident NTM-PD. Endogenous estrogen exposure was evaluated using age at menarche, age at menopause, and reproductive period (duration between age at menarche and age at menopause).

RESULTS

During a median of 8.4 (interquartile range, 8.2-8.7) years of follow-up, 0.1% of participants (1,818/1,400,095) developed NTM-PD, with an incidence rate of 0.15/1000 person-years. Multivariable Cox regression analyses showed no significant relationship between endogenous estrogen exposure (age at menarche, age at menopause, and reproductive period) and risk of NTM-PD. In contrast, duration of HRT showed a significant dose-response relationship with incident NTM-PD even after adjustment of demographics and reproductive factors (adjusted hazard ratio [95% confidence interval]; 1.30 [1.12-1.51] in HRT for < 2 years, 1.28 [1.03-1.59] in 2-5 years, and 1.65 [1.33-2.05] in ≥ 5 years).

CONCLUSIONS

While there was no significant association with endogenous estrogen exposure, HRT was monotonically associated with increased risk of NTM-PD in postmenopausal women.

The 6-minute walk test predicts mortality in a pulmonary nontuberculous mycobacteria-predominant bronchiectasis cohort

Background

Bronchiectasis is a chronic lung condition frequently associated with nontuberculous mycobacteria pulmonary (NTM) disease. Persons with these conditions are at increased risk of mortality. Patient reported outcome (PRO) instruments and the 6-minute walk test (6MWT) have been shown to predict mortality for several lung conditions, but these measures have not been fully evaluated for bronchiectasis and NTM.

Methods

We conducted a retrospective cohort study among adult patients enrolled in a natural history study of bronchiectasis at the National Heart, Lung, and Blood Institute. Electronic medical records were queried for demographic, clinical, microbiologic, radiographic, and PRO instrument data: St. George’s Respiratory Questionnaire (SGRQ), Medical Research Council Dyspnea Scale, and the Pulmonary Symptom Severity Score (PSSS). The study baseline date was defined as the patient’s first visit after January 1st, 2015 with a SGRQ or 6MWT completed. Follow-up was defined as the interval between the study baseline visit and date of death or December 31st, 2019. Sex-stratified Cox proportional-hazards regression was conducted to identify predictors of mortality. Separate models were run for each PRO and 6MWT measure, controlling for age, body mass index (BMI), fibrocavitary disease status, and M. abscessus infection.

Results

In multivariable Cox proportional-hazards regression models, the PSSS-severity (aHR 1.29, 95% CI 1.04–1.59), the 6MWT total distance walked (aHR 0.938, 95% CI 0.896–0.981) and distance saturation product (aHR 0.930, 95% CI 0.887–0.974) independently predicted mortality. In addition, BMI was significantly predictive of mortality in all models.

Conclusions

The 6MWT and a PRO instrument capturing symptom severity are independently predictive of mortality in our cohort of bronchiectasis patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07054-6.

Factors affecting in-hospital mortality of non-tuberculous mycobacterial pulmonary disease

Background

The incidence and prevalence of non-tuberculous mycobacterial pulmonary disease (NTM-PD) are reportedly increasing in many parts of the world. However, there are few published data on NTM-PD-related death. Using data from a national inpatient database in Japan, we aimed in this study to identify the characteristics of patients with NTM-PD and clinical deterioration and to identify risk factors for in-hospital mortality.

Methods

We examined data from the Diagnosis Procedure Combination (DPC) database in Japan from July 2010 to March 2014. We extracted data for HIV-negative NTM-PD patients who required unscheduled hospitalization. We evaluated these patients’ characteristics and performed multivariable logistic regression analysis to identify risk factors for all-cause in-hospital mortality.

Results

A total of 16,192 patients (median age: 78 years; women: 61.2%) were identified. The median body mass index (BMI) was 17.5 kg/m² (IQR 15.4–20.0). All cause In-hospital death occurred in 3166 patients (19.6%). The median BMI of the patients who had died was 16.0 kg/m² (IQR 14.2–18.4). Multivariable analysis revealed that increased mortality was associated with male sex, lower BMI, lower activities of daily living scores on the Barthel index, hemoptysis, and comorbidities, including pulmonary infection other than NTM, interstitial lung disease, pneumothorax, and malignant disease.

Conclusions

We found associations between being underweight and having several comorbidities and increased in-hospital mortality in patients with NTM-PD. Preventing weight loss and management of comorbidities may have a crucial role in improving this disease’s prognosis.

Association between serum anti-glycopeptidolipid-core IgA antibody titers and clinical characteristics of Mycobacterium avium complex pulmonary disease

OBJECTIVES

Mycobacterium avium complex pulmonary disease (MAC-PD) can be serologically diagnosed according to the presence of anti-glycopeptidolipid (GPL)-core IgA antibodies. However, few studies have examined the association between serum anti-GPL-core IgA antibody titers and the clinical characteristics of patients with MAC-PD.

METHODS

From April 2014 to June 2019, the levels of anti-GPL-core IgA antibodies in 489 MAC-PD patients were determined at the current institute. Of them, 89 patients fulfilled the criteria of the American Thoracic Society and the Infectious Diseases Society of America statement on the diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Patients were categorized into the antibody strong-positive (n = 27), weak-positive (n = 32), and negative (n = 30) groups according to their serum anti-GPL-core IgA antibody results. Their clinical characteristics were retrospectively compared.

RESULTS

Disease progression requiring treatment and extensive radiological findings were significantly abundant in the strong-positive group compared with the weak-positive group. Clinical characteristics of the antibody weak-positive and negative groups did not significantly differ.

CONCLUSIONS

The findings revealed that serum anti-GPL-core IgA antibody titers are useful for diagnosing MAC-PD and also for predicting the risk of exacerbation.